Abstract Title: Transtensional deformation and spatial and temporal 
partitioning of fault activity along the Sierra nevada-Great Basin boundary zone

Abstract Author(s): Schweickert, R.A. (Univ. Nevada, Reno), Smith, K.D., 
Lahren, M.M., and Howle, J.

Abstract: Dextral transtensional deformation is occurring along the Sierra 
Nevada-Great Basin boundary zone (SNGBBZ) at the eastern edge of the Sierra 
Nevada microplate. In the Lake Tahoe region of the SNGBBZ, transtension is 
partitioned spatially and temporally into domains of north-south striking 
normal faults and transitional domains with conjugate strike-slip faults. The 
normal fault domains, which have had large Holocene earthquakes on 
east-side-down faults but account only for background seismicity in the 
historic period, primarily accommodate east-west extension. In the transitional 
domains, older sets of faults show SW-side down displacements and root beneath 
the Sierra. These older faults have had moderate Holocene and historic 
strike-slip earthquakes, are currently seismically active, primarily record 
north-south shortening. Through partitioned slip, the upper crust in this 
region undergoes overall constrictional strain. The importance of the older, 
SW-dipping faults is that they probably affect Sierran crustal thickness and 
have been reactivated as conjugate strike-slip faults in the current 
deformation regime.